After the Soviet Union broke America's atomic monopoly in 1949, several prominent scientists and politicians favoured the development of the hydrogen bomb, a fusion weapon hundreds of times more powerful than the bombs that the Manhattan Project had built.

ECONOMIST: Robert Oppenheimer

Acting alone, gravity would cause stars to collapse completely, but as long as energy is produced at their centers by nuclear fusion (the joining of atomic nuclei to form new elements, as in a hydrogen bomb), the star is heated and puffed up.

CNN: Why gamma-ray burst shocked scientists